Railway signaling



P.TATZ

RAILWAY SIGNALING Filed Dec. 2, 1925 ll l i i INVENTOR PAULTATZ TO'RNEY Patented J am. 3, 1928.

UNITED srares" PA ENT T OFFICE.

PAUL TATZ, OF BERLIN, GERMANY, ASSIGNOR T0 GESELLSCHAFT FUR DRAHTLOSE TELEGRAPI-IIE M. B. H HALLESCHES, OF BERLIN, GERMANY, A CORPORATION OF GERMANY.

RAILWAY SIGNALING.

Application filed December 2, 1925, Serial No. 72,649, and in Germany December 6, 1924.

This invention relates to the art of railway signaling and deals particularly with the provision of a railway si naling system which is certain and dependaIllein its operation.

It is old to provide a travelling train with an electric oscillation generator most suitably an electron tube. For cooperation with this generatorthere are placed energy absorbing circuits along the tracks such as oscillation circuits tuned to the frequenc of the oscillation generator carried bythe ocomotive and which are so coupled to the device carried by the locomotive that as the same passes over these track devices there is a marked energy absorption and the oscillatory state of the transmitter is thereby altered. Aconvenient relay or other device is provided to be actuated by this change in the state of the oscillation generator. As a general rule, the apparatus has been so designed that the tuned circuit mounted along. the track was coupled with a circuit determining the frequencyof the tube transmitter. Now in order that sufficient energy absorption may be produced it is necessary to provide for exact tuning between the oscillation circuit along the track and the oscillation .cir cuit ofthe tube-transmitter for the reason that it is possible to attain a transfer of. ohmic resistance only if such condition prevails; In the event that there is merely untuning of the circuit the resulting efi'ect'is merely an alteration of the frequency of the transmitter or generator tube through the -change of the effective inductance of the transmitter circuit. Therefore, if the relay or recording device responds only to energy absorption it-is apparent that when detuning takes place between the transmitter and the circuit arranged along the track the apparatus is liable to fail in its operation.

It is an object of this invention to obviate v I the above disadvantage. Thisresult is obtained by providing the moving train with an oscillation generator and a track device in the usual manner. However, instead of coupling the trackside circuit with the circuit which governs the frequency of the oscillation generator, I provide another separate oscillating circuit to which the track device is designed to be coupled. As a result of tbisarr gem nt wh n the c ndition of detuning arises the generator-fails completely to oscillate, which condition may be readily indicated by a suitable indicating device. The manner in which I carry out this invention will be better understood from the foluum tu e generators which is provided with the circuit S, designed to maintain the tube in a state of oscillation. B indicates a suit able source of direct current forthe operation of this system; the tube G and the circuit S are arranged in the well-known volt age divider connection. It is well-known that in this form of connection a high frequency resistance must be inserted in the supply lead in order that short circuiting across the battery B may be avoided. It is common. practice to use choke coils for this purpose, but in accordance with the resent invention I provide a circuit S tune to the transmission frequency. This circuit S acts, as. a high frequency resistance and chokes back the radio frequency oscillations generated by the tube G as aresult of which the circuit-S is enabled to keep the tube G in oscillation. I also provide the relay R which is designed to indicate the fact that the tube has stopped oscillating The transformer K is associated with the track and is adapted to be coupled to the circuit 8, as the tram passes over the track device.

- The operation of the device is as follows:

""K is passed over b the train, energy will be absorbed by circuit. K and the reaction of circuit K on the inductance coil of circuit S will change the effective resistance of the latter circuit, thereby changing suddenly the plate potential and the plate current. This change of plate potential with respect to the grid upsets the oscillatory condition of the tube and causes it to stop oscillating. The

non-oscillatory condition is indicated by its 'afiecting relay It, The position of the relay tlmsserves to indicate to the train operator when the train is passing by a trackside device.

Having thus descri 5 claim: 2

In a railway signaling system, the combination of a train device and a track-side device, said train device comprising a vacued my invention I um tube scillator having a plate circuit and a grid circuit, a tunedcircuit in said grid c1rcu1t, a battery 1n sald plate circuit, a connectlon between sald battery and an intermediate point of said tuned circuit, a tuned circuit in said plate circuit adapted when reacted upon by said track-side device to render the tube non-oscillatory and means to indicate said non-oscillatory condition.

PAUL TATZ. 

